Musical sound recording system and method

ABSTRACT

A musical selection is recorded on a first sound track driven at a speed corresponding to the frequency level of the key in which the selection is to be played. The same selection, or different harmony parts of that selection, are then successively played in different keys and are recorded on separate sound tracks at speeds corresponding respectively to the frequency or characteristic frequency of each different key selected. In each successive recording, the first recording is played back for reference purposes to provide the proper tempo for recording at each different speed. Thereafter, the recordings on each separate track are played back simultaneously at the reference speed and may be rerecorded on a single track. Although the given selection is recorded at different speeds, when played back at the reference speed each recording will blend and harmonize with the first recording. A speed changing mechanism is employed with a magnetic tape drive to carry out the method on a single tape provided with multiple sound tracks.

United States Patent Lowell Edward Beisner 8545 W. 64th Ave... Arvada, Colo. 80002 [21 Appl. No. 786,517 [22] Filed Oct. 3, 1968 Division of Ser. No. 616,717, Feb. 16, 1967, abandoned. [45] Patented Feb. 2, 1971 [72] Inventor [54] MUSICAL SOUND RECODDING SYSTEM AND Primary Examiner-Harry N. Haroian Attorney-J0hn E. Reilly ABSTRACT: A musical selection is recorded on a first sound track driven at a speed corresponding to the frequency level of the key in which the selection is to be played. The same selection, or different harmony parts of that selection, are then successively played in different keys and are recorded on separate sound tracks at speeds corresponding respectively to the frequency or characteristic frequency of each different key selected. In each successive recording, the first recording is played back for reference purposes to provide the proper tempo for recording at each different speed. Thereafter, the recordings on each separate track are played back simultaneously at the reference speed and may be rerecorded on a single track. Although the given selection is recorded at different speeds, when played back at the reference speed each recording will blend and harmonize with the first recording. A speed changing mechanism is employed with a magnetic tape drive to carry out the method on a single tape provided with multiple sound tracks.

PATENTEU FEB zlsm $560,000

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HEEIHEIHHEEIH I L l INVENTOR LOWELL E. BEISNER ATTO NEY MUSICAL SOUND RECORDING SYSTEM AND METHOD This is a division of application Ser. No. 616,717 filed Feb. 16, 1967 now abandoned.

This invention relates to a new and useful method and means for recording musical sounds on one or a plurality of sound tracks, as well as for the rerecording of musical sounds, to create unique and distinct but harmonious musical effects.

Various techniques and systems have been devised for playing and recording musical selections to create unusual and distinct sound effects. In one technique, referred to as the octave effect, a matrix of a musical selection is first recorded, then the same selection is recorded at an octave interval from the first recording, for example, by reducing the speed to onehalf or by increasing to twice the speed of the original recording. A musical octave occurs, since one of the tracks records at one speed and the second track records at one-half or double the speed; and when the recordings are combined in synchronism with one another will create distinct sound effects. ln recording at octave intervals, no pitch or key change is required, and as would be expected complete harmony can be achieved. Ordinarily however it would not be expected that a musical selection, or parts of a musical selection, could be recorded in different pitches or keys, at other than octave in tervals apart, and successfully combined into a single recording to produce unique but harmonious musical sounds, because of the discord between many of the notes. Yet, a number of advantages are apparent from a system which would permit playing and recording of a musical selection, or different parts of a selection, in different keys and consequently at different speeds. For example it would be possible to create unique and distinct sound effects and tones. Also it would avoid the problems inherent in playing in certain registers of many musical instruments where it is often difficult to obtain a true pitch or tone, or playing in keys and at tempos wherein it is very difiicult to execute certain musical passages at conventional speeds.

it is therefore an object of the present invention to provide for a new and useful system for recording and rerecording musical sounds and selections to create unique and distinct but harmonious musical effects and which is readily conformable for use in vocal or instrumental recordings and virtually any convention or known method for creating musical sounds.

It is another object of the present invention to provide apparatus for creating unique and distinct musical sounds and arrangements through commercially available monaural or stereophonic recording systems, such as, magnetic tape systems or recording discs; and further to provide an apparatus for shifting a sound track drive to one of a number of different speed settings, corresponding to a different characteristic frequency level of a different note or key in the musical scale and to accomplish the same in a simple, accurate manner.

It is a still further object of the present invention to provide a new and useful apparatus for recording musical selections which will greatly facilitate playing of different selections, particularly in executing and playing difficult passages while enabling close accurate control over the pitch or frequency of each note and eliminating the distortion often introduced in playing certain registers of a musical instrument; and furthermore to provide for an improved, simplified apparatus and system readily conformable for use with different types of recording devices in carrying out the method of the present invention.

The objectives of the present invention are realized essentially by synchronizing and combining musical tones which are separately recorded in different keys. As a basic illustration, the C note may be played and recorded on a first sound track driven at a speed corresponding to the characteristic frequency of the C note. A G# note is then recorded on a separate sound track driven at a difi'erent speed corresponding to the characteristic frequency level of the G# note. When the two notes are played back simultaneously at the speed of the first LII recording, that is, the speed corresponding to the frequency of the C note, the G# note will be heard at the same frequency or pitch as that of the C note, that is to say, the G# note will be transformed to a C note. If the G# note were played originally within the octave below C, it would result in a speed up in recording of that note at the higher frequency level, and while the pitch or tone of the G# note would be the same as the C note, it would have a distinct tone quality with a somewhat different timber" as a result of compressing the sound vibration of that note at the higher speed. Surprisingly, when a succession of different notes is played and recorded in the key of C, and the same succession of notes then played and recorded in the key of G#, where the tracks are in each instance driven at speeds corresponding to the frequencies of each different respective key, and thereafter the tracks are simultaneously played back at the higher speed setting in the key of C it is found that the notes are in perfect harmony but with a distinct tone quality contributed by the recording originally in the key of G#, again resulting from the speed up in play and from the compression of sound vibrations. To synchronize the separate recordings, it is essential that the second recording in the key of G# be at a correspondingly slower tempo and which for example can be easily regulated by playing back the first recording at the slower speed and playing the second succession of notes in the key of G# in tempo with the first recording. Similarly, parts or all of a musical selection may be played for separate recording at different speed settings corresponding to the characteristic frequency of different selected keys then combined into a single recording at the reference speed or in the reference key. For example, the melody part of a selection may be played in its original key, and one or more harmony parts played in a different key or a number of different keys; and thereafter each of the recordings is played back simultaneously in the original key and rerecorded on a single track.

Although the method of the present invention may be practiced by recording on a plurality of separate recording systems, each capable of running at different speeds, it is of course highly desirable, most practical and efficient to carry out the same on a single recording unit, such as, for example a magnetic tape recording device. To accomplish this according to the present invention, different forms of speed changing mechanisms have been devised for regulating the speed of the tape drive in accordance with the frequency level of the note or key in which the selection is to be rerecorded. In this relation, each note or key in each different octave interval emanates a sound vibration having a characteristic frequency level which can be accurately measured, and the pitch or frequency level of the musical tone or note when recorded will depend upon the speed of motion of the sound track. Accordingly, to record a given note or a succession of notes in a selected key, the sound track should be driven at a speed corresponding to the frequency of that note or key. An effective way of shifting the drive mechanism for the sound track to different speeds corresponding to different characteristic frequencies with optimum stability and accuracy is through the selection and design of different gear or pulley ratios, each ratio being correlated with a different discrete frequency. Another simple and effective way of accomplishing the same end is to provide a series of drive bushings in which each drive bushing is accurately sized to provide a different speed ratio corresponding to a different frequency level. In accordance with the present invention speed settings may be selected to correspond accurately with different notes withinan octave as well as with notes in different octaves.

The above and other objects, advantages and features of the present invention will become more readily understood and appreciated from a consideration of the following detailed description of preferred and alternate forms of the present invention when taken together with the accompanying drawings, in which:

FIG. 1 is a schematic illustration of one embodiment of the present invention adapted for use in a magnetic tape recording unit.

FIG. 2 illustrates a series of bushings in elevation and being graduated in size to determine the speed ratio of each recording, in accordance with another form of the present invention.

FIG. 3 is a view of a type drive spindle for a magnetic tape system adapted to receive each of the bushings shown in FIG.

FIG. 4 is an end view of the bushings shown in FIG. 2; and

FIG. 5 illustrates the relative disposition of one of the drive bushings shown in FIGS. 2 and 4 in a magnetic tape system.

As a setting for the present invention, both illustrative embodiments are shown as part of a magnetic tape recording unit and which is merely representative of the adaption and use of the method and system of the instant invention to various different forms of recording systems, as hereinafter suggested. Conventionally, the magnetic tape recording unit as shown consists of a motor drive M for driving a capstan drive shaft S having a drive roller B. The external surface of the bushing is engageable with the outer peripheral surface of an enlarged, rubber-faced capstan roller C, the latter being spring-loaded to bear against the drive roller B. A magnetic tape T is threaded from a cartridge not shown, for advancement through the contact area between the members B and C. In accordance with well-known practice, an individual recording may be transposed on one of a number of parallel channels or tracks on a tape through a recording head for each track; and a separate pickup head for each track may alternately be advanced into sound-transmitting relation to the track either for recording or for playing back a recording from the track through an amplifier system. In this relation, it is possible to play back simultaneously on one or more tracks while recording simultaneously on one or more tracks, or to individually record or play back on each separate sound track. A commercially available recorder of this type is the Roberts 400x recorder manufactured and sold by Roberts Electronics Division of Rheem Manufacturing Co.

In practicing the method of the present invention it is highly desirable that the widest latitude of selection or choice of different keys within an octave and at different octave intervals be made available while at the same time retaining optimum stability and accuracy in drive speeds at each different speed setting. Again, the frequency level of the sound vibration of each note or key can be accurately measured and a speed ratio between the power source and tape drive can be selected to match each frequency level. In order to control the tape drive speed in accordance with a selected speed setting corresponding to the frequency level of a key, a speed-changing mechanism is interposed between the motor drive M and the tape drive. In FIG. 1, the mechanism comprises an intermediate drive shaft 22 being joumaled for rotation in suitable bearings, not shown, and being aligned in spaced parallel relation to the drive shaft S. One end of the shaft 22 has a step pulley arrangement 24 over which is trained a belt 25 from another series of step pulleys 26 on motor drive shaft 23, the intended function of the step pulleys 24 and 26 to be hereinafter described in more detail. A plurality of key step pulleys 28 and 30 are fixed to the shafts S and 22 respectively, and the pulleys 28 and 30 are stepped, that is, of progressively increasing diameters, in opposite directions, and are arranged such that each pair of aligned pulleys between the shafts is sized to produce a different selected speed ratio. In the embodiment shown, 13 pulleys, graduated in diameter, are keyed on each shaft and each of the 13 pulley-pairs is sized to produce a different note and half-note in a musical scale. A common drive roller 32 is mounted on a spindle 33 in parallel but offset relation above and intermediately between the shafts S and 22 whereby to simultaneously engage aligned pulley-pairs and transmit the drive speed from one of the drive pulleys 28 through the aligned driven pulley 30 on the tape drive shaft S. The drive roller 32 is shiftable for axial advance- .ment to each different selected pulley-pair through suitable purpose of swinging or pivoting the drive roller 32..into.and. away from engagement with the step pulleys; and is further: movable in an axial direction, such as, by means of push-pull knob 38 to shift the drive roller 32 axially into alignment with different selected pulley-pairs. It will benoted that the rackintermeshes with the outer toothed surface of a gear 36 in order to rotate the gear as the roller 32 is shifted to a selected pulleypair; and the surface of the gear is provided with key signatures as illustrated whereby to indicate through a suitable index opening in a panel, not shown, the disposition of the drive roller opposite a pulley-pair corresponding to the same key signature and desired speed setting. In advancing the drive roller, the knob 38 is rotated slightly to lift the drive roller off the pulley surfaces for axial advancement to the next speed setting whereupon the drive roller is lowered into frictional, engagement with the aligned pulley surfaces.

Again, each note or key in the musical scale has a particu-. larly characteristic or discrete frequency level which can be measured, and each of the 13 step pulley-pairs is dimensioned to establish a different selected speed ratio or setting, each corresponding to the discrete frequency level of each different note or key within an octave, as illustrated in FIG. I. Table I lists the abbreviated pulley or speed ratios and corresponding tape speeds which willmatch international musical pitches or keys.

TABLE 1 Tape speed, inches per second It will be noted that a speed setting is available for each note and half-note in the musical scale within an octave interval. In. order to enable octave speed jumps, the octave step pulleys 24 and 26 are comprised of aligned pulley-pairs 40, 41 and 42 which will effect changes in speed in the ratio of one-half, oneto-one, and two-to-one, respectively, between the motor drive and the pulley drive shaft. The desired ratio is selected, for example, by shifting the belt drive, represented in dotted form at 25, over an aligned pulley-pair corresponding to the desired ratio.

In the use of the recording system according to the method of the present invention, the motor drive is energized and the drive roller 32 is shifted to the desired reference key or speed setting for a particular musical selection, thereference key being the key in whichthe music is originally written. The artist then plays the selection in the reference key and records on a first sound track. The tape is then rewound to the starting position. For the purpose of illustration, the artist may then record the same selection in a lower key and at acorrespondingly loweg frequency and speed setting, such as,.for example thekey of D. For proper correlation with the first recording, the first recording is played back to the artist, for example, through headphones, at the reduced speed setting selected for the second recording so that the music recorded on the second track will be in tempo with the first recording.

In this connection, it is necessary to compensate for different speeds between recordings since ultimately all tracks will be played back at the same speed. Still another key may be selected for recording on a third sound track, and in the same manner the artist would play the selection, or a harmony part of the selection, in the key selected for recording on that; i

track. Assuming that the magnetic tape is designed for fourtrack recording, when the first three tracks are filled the recordings are simultaneously played back at the reference speed and are combined or superimposed by recording on the last, or fourth track. Once combined, the first three tracks may be utilized for additional recordings in different keys as desired; or at any stage the recordings may be combined on a single track.

The recording technique and system devised, being quite versatile, lends itself peculiarly to the skill of the musician in playing, composing and recording different musical selections or sounds. The key or combination of keys selected may or may not be at harmonic intervals, although particularly good results are obtained at harmonic intervals within an octave. Different sound effects in different keys may be tried or discarded at the will of the musician. Moreover, difficult passages may be played at slower speeds and at frequency levels best suited to a particular instrument and thereafter rerecorded at the reference speed.

The matrix or reference recording may be made at any given recording speed and in general is selected to match the design speed of the recording system. For example, as shown in FIG. 1, the system or reference key is selected for seven and one-half inches per second tape speed which at present is the most common speed for tape recording. Again however twelve additional speeds ranging between seven and one-half inches per second and three and three-quarters inches per second are provided to synchronize with the notes of the musical scale and also with each of the key signatures. It will therefore be evident that any number of key combinations can be recorded making it possible for one musician to accompany himself, or for a group of musicians to record in unison. Where desired it is also possible to incorporate the octave effect through the speed selection ratio afforded between the pulleys 24 and 26 as a separate part of the drive linkage. To obtain utmost accuracy, suitable allowance should be made in the motor drive for vernier adjustment between the drive motor and step pulley input shaft as well as for overall speed changes at octave intervals.

Of particular importance in varying the frequency of the recording is that as the speed of each original recording is increased or decreased a change in the nature of the sound takes place. In notes recorded at one speed and rerecorded at a higher speed a transformation takes place in several areas of the notes. For example the note has a shorter period of buildup to the point of maximum amplitude, followed by a relatively short decay period. The reverse effect is created where the notes are rerecorded at different reduced speeds. Normal overtones for notes of some frequencies are transformed to higher notes and again many variations and transformations in frequencies of the notes can be developed depending upon the skill of the musician.

For the purpose of illustration, Table II sets forth the actual, theoretical cycles per second to decimal places in each note. The frequencies given were derived to an accuracy of one part in 600,000,000purely for reference purposes, and are based on an A note at 440 cycles per second, which is considered as the established international pitch. lf frequencies are required in octaves above or below Table II, it is merely necessary to multiply by two, four, eight, 16 or divide by two, four, eight or 16, keeping in mind that the frequency of each octave doubles in logarithmic progression in progressing upwardly or downwardly. The frequencies on Table ll fall within the range of most published manuals for tuning musical instruments and are given because the success in the system of recording depends on accuracy for professional results. A machine constructed with good quality components, and accurate steps for the keys, can be used by the most discriminating recording studio with assurance of perfect satisfaction of pitch.

TABLE II Ratio Key Cycles per second 1.000,000,000,000 A 440 1.059,463,094,900 A# 466. 163, 761,800 1.122,462,049,666 B 493. 883, 301,853, 470, 771 1 523. 251, 131, 599, 793, 380 1. 554. 365, 263, 347,188, 302 1. 587. 329, 537, 616, 307, 913 1. 622. 253, 969, 690, 614, 872 1. 659. 255, 116, 614, 398, 222 1 F 698,456,466, 227, 621,877 1.681,792,836,855,491 F# 739. 988,849,404,014, 889 1.781,797,444,236,850 G 783. 990, 876, 650, 812,893 1.887,748,634,683,329 G# 830. 609,400, 574, 399,077 2,000,000,000,000,000 A 880. 000, 000, 000, 000, 000

An alternate form of speed-changing mechanism is illustrated in FIGS. 2 and 3 wherein a change in speed settings is effected through the use of interchangeable bushings. Each bushing is of a different outside diameter to establish a tape drive speed ratio between the motor drive M and the spindle S to control the speed of tape T between the drive bushing B and the capstan roller C corresponding to a selected frequency level for each note, as presented in Table III. For the purpose of illustration the diameter of the shaft S is 0.2359 inches, in the absence of a bushing, for recording in the key of A.

TABLE III Bushing diameter Key: (in inches) A# 0. 249927 B 0. 264788 C 0. 2805339 C# 0. 2972153763 D 0. 3148887 D# 0. 33361 E 0. 353451 F O. 3745 F# 0. 3967349308 G 0. 420326 G# 0. 44532 A 0. 47180000 A# 0. 499855 Within practical limits, the musician or recording artist may then select and employ bushing diameters according to each desired speed setting for a different note within an octave or for notes of different frequencies in different octaves. The method or procedure followed in preparing each recording and combining into a single recording is the same as hereinbefore described, and a bushing is selected and placed on the drive spindle for each different key to be recorded, Of course, use of different selected drive bushings eliminates necessity of the step pulley arrangement as disclosed in FIG. 1; instead, the motor drive M is connected directly to the tape drive spindle S. Again, when all tracks are completed and played simultaneously at the reference speed everything will harmonize musically but the automation will have been rearranged to modify the tone dwell and in many cases to add new harmonies to the total ensemble.

From the foregoing it will be appreciated that different mechanisms may be utilized in regulating the tape drive speed and modifying the same to correspond to different selected keys and frequency levels. For example the step pulleys may be used in combination with virtually any type of motor drive, such as, a synchronous speed motor drive or speed governor drive. Also the step pulleys may take the form of tapered cone pulleys engaging other pulleys in a manner whereby the ratio is changed by relocating the tapered cone pulley with respect to the associated pulley. Variable speed may also be obtained by armature control of the drive motor, such as, by regulating the speed of the drive motor with a frequency control device,

such as, the Tuning Fork Oscillator Model G Standard Series manufactured and sold by Fork Standards, Inc. of West Chicago, Illinois. Of course, a variable speed gear drive would be an accurate method of obtaining different selective speed settings but is not as satisfactory on account of the noise generated by the gears.

While preferred and alternate embodiments of the present invention are hereinbefore set forth and described together with preferred methods and techniques for carrying out the present invention it is to be understood that various modifications and changes may be made in the systems described without departing from the spirit of the present invention.

lclaim:

1. In a musical sound recording system having at least one sound track, sound recording and playback means for each sound track and drive means for driving each sound track including a drive spindle, the improvement comprising a speed changing mechanism defined by a plurality of removable drive bushings alternately disposable on said drive spindle, each bushing being of a different diameter to establish a different speed ratio between the drive spindle and the 'magnetic tape, each different speed ratio matched with a different discrete frequency level of different selected keys within each octave of a musical scale and speed selecting means for alternately selecting one of said speed settingsfor interengagement with said drive means to control the drive speed of said sound track.

2. In a musical recording system according to claim 1, said bushings further characterized by establishing different speed settings corresponding to each note and half-note within an octave interval of the musical scale.

3. In a musical sound recording system according to claim 2, said speed changing mechanism further including a second series of speed settings each corresponding to a different discrete frequency level of notes at octave intervals. 

1. In a musical sound recording system having at least one sound track, sound recording and playback means for each sound track and drive means for driving each sound track including a drive spindle, the improvement comprising a speed changing mechanism defined by a plurality of removable drive bushings alternately disposable on said drive spindle, each bushing being of a different diameter to establish a different speed ratio between the drive spindle and the magnetic tape, each different speed ratio matched with a different discrete frequency level of different selected keys within each octave of a musical scale and speed selecting means for alternately selecting one of said speed settings for interengagement with said drive means to control the drive speed of said sound track.
 2. In a musical recording system according to claim 1, said bushings further characterized by establishing different speed settings corresponding to each note and half-note within an octave interval of the musical scale.
 3. In a musical sound recording system according to claim 2, said speed changing mechanism further including a second series of speed settings each corresponding to a different discrete frequency level of notes at octave intervals. 